Prefabricated or Industrialised Building System (IBS) component has been widely used in the housing construction sector that facilitates mass production. An IBS building uses ingredients like prefabrication, standardisation, methods of production and quality control (Gann, 1996). The engineering advantageous in using IBS in construction include elimination of waste, precision and quality control in production, optimisation of time and sustaining and protecting the environment during construction. These benefits encourage IBS as a construction technique and this factor is one of the prime factors for promoting the IBS building system around the world. Unfortunately, designers still have problem to creatively experiment with IBS components during a building project's design phase and prefabrication.
The level of standardisation and prefabrication process is considered very low (Noguchi, 2003). Despite its premature growth in the construction industry, IBS construction is a preferred construction method in developing countries. The targeted benefit of IBS implementation is its objective to minimise dependency on foreign labour in construction projects. However, IBS implementation meets the supply demand barrier. Economic volume, general readiness and social acceptability of IBS make the construction technology less appealing (Zuhairi 2008). Moreover, although the prefabrication building process puts emphasis on the mass production, repetitive design layout is blamed for causing monotonous barrack-liked complex (Thanoon 2003).
Gib (1999) identified three categories of offsite prefabrication; namely, non-volumetric, volumetric, and modular building, but he argued that the line dividing each type is flexible. When Gib's concepts are applied into prefabricated house design in term of architectural perspective, there is a miss-coordination between the spatial dimensioning of physical building element and the functional building design element therefore making it not appropriately moulded into fabrication of the house's space design. Yet Gib's system also did not address the assembly and disassembly of industrialised building systems. It is also noted that there is no timber building system existing for prefabrication since the conventional wooden construction joints have been used in the prefabrication process. Additionally, there is nil assembly of industrialised building system in the form of non-volumetric pre assembly for volumetric pre assembly and/or modular building.
Schindler was reported attempting to develop new construction system for housing whereby the construction system enables to reduce construction cost, improve in building efficiency, increase speed of fabrication interchangeability of parts, reduce number of labours, provide durability and provide better design (Jon Ho Park 2004). Schindler had identified the needs of building assembly in prefabrication but his construction system was complicated that it reduced prefabrication flexibility of the designed assembly. To date, there is a lack of pre assembly system that is flexible enough to simplify the assembly in prefabricated timber building construction, especially when the assembly system is applicable only in precast concrete panel systems and more so in the less developed timber building assembly.
Historically those taking standardisation seriously have always struggled to resolve the conflict between uniformity and variation, between standardisation and flexibility (Gibb 2004). This conflict still not been solved.
In one of the prior art, it discloses a modular building system which includes a prefabricated desk system having a plurality of rectangular flooring modules. However, the system is modular form but not in the form of building component assembly. Moreover, the floor modules of this prior art are sandwiched with joist and connector.
Another prior art discloses a joint connector device and a method for assembling prefabricated building panels. This prior art invention includes an L-shaped cove channel joint connector device for joining prefabricated structural building panel and its method of assembly. However, it does not have flexibility for angular or radial walls construction.
The invention of this study focused on the design assembly for an industrialised building system in which degree of flexibility in design form can be rejuvenated. This invention stating the prefabricated building assembly is not only an engineering process. It is an amalgamation of both design cum engineering methods and mechanics.